The invention relates to suspended trolley lines, and, more particularly, to suspension monorail trolleys.
A suspended line with an undercarriage guided along a profile rail is disclosed in German public-disclosure document DE 196 10 118 A1, published Sep. 19, 1996. The undercarriage essentially consists of a frame and a running wheel capable of being driven along the rail by an electric motor located on the frame of the undercarriage. The running wheel has a bearing surface which rolls in contact with an upper bearing surface of the profile rail to move the undercarriage along the rail. A supplemental rail is occasionally positioned parallel to the profile rail at least in areas where the profile rail deviates from horizontal. Frictional wheels are provided which roll in contact with both a surface of the supplemental rail and the bearing surface of the running wheel, thereby increasing the application force of the running wheel on the bearing surface of the profile rail and functioning as supplemental drive elements in areas where the supplemental rails are present. Two frictional wheels are provided for this which are located in front of and behind the axle of the running wheel and above the axis of the running wheel. The frictional wheels are each secured on the frame through toggle joints and are additionally connected with each other through a connecting rod connecting their axles. The connecting rod is located above the running wheel and extends in the direction of motion of the trolley. The axles of the frictional wheels are supported in the connecting rod and are movable along the rod in the direction of motion. This allows the frictional wheels, in cases of tolerance variations in the spacing between the bearing surface of the profile rail and the corresponding surface of the supplemental rail, to balance out the variations through movement towards each other or away from each other. This ensures a maintenance of the contact pressure of the running wheel on the surface of the profile rail, and of the frictional wheels on the supplemental rail. In order to achieve this, the axles of the auxiliary wheels impinge upon each other within the connecting rod through a spring element. Furthermore, the levers of the L-shaped toggle joint are connected with each other through spring elements or absorption elements, in order to avoid oscillations or vibrations of the Furthermore, the levers of the L-shaped toggle joint are connected with each other through spring elements or absorption elements, in order to avoid oscillations or vibrations of the frictional wheels when running along the supplemental rail. A secure fitting of the auxiliary frictional wheels on the running wheel should also provide for an averaging out of the contact pressure in all of the route sections of the trolley system.